Grouping is where a keyword list becomes a plan. The rule is simple to state and hard to apply: queries that want the same thing belong on one page, and queries that want different things do not, however similar the words look. Getting this wrong in either direction is expensive. Split too finely and you publish thin pages that compete with each other; group too broadly and you publish a page that half-answers several questions and satisfies none of them.
Group by what the searcher wants, not by word overlap
Two queries sharing most of their words can want completely different things, and two queries sharing none can want the same thing. The reliable signal is what a person would be satisfied by. Write the want down in a few words beside each query before you group anything, and the groups become obvious in a way that sorting alphabetically never makes them.
Let the results check your grouping
Search two queries you think belong together and compare what comes back. If broadly the same pages rank for both, search engines already treat them as one want and one page is right. If the two result sets barely overlap, they are different wants whatever your instinct says. This takes a minute per pair and it settles most arguments.
The opening-paragraph test
Try to write the first paragraph of the page so that a person arriving from any query in the group would keep reading. If you can, the group holds. If the paragraph has to hedge, or spends its first sentence explaining that this page covers two things, the group is two pages. This is the same test that catches a page trying to serve both a definition and a buying decision.
Record the grouping, because it is a decision
A grouping is the most reusable thing keyword research produces and the thing most often lost, because it lives in a spreadsheet tab that gets rebuilt. Kept properly, it tells the next person which page a new query belongs to instead of leaving them to create a fifth page about the same want.
Questions people ask about how to group keywords
How do I know two keywords belong on the same page?
When somebody typing either would be satisfied by the same page, and when the results for both are broadly the same pages.
How many keywords per page?
However many share one want. That is often three to ten phrasings, and occasionally one.
What happens if I split too finely?
Several thin pages compete for the same want, and a search engine picks one, usually not the one you meant. Consolidating is the fix.
Does Longtailo do the grouping?
It keeps it. The judgement about what shares a want is yours; Longtailo holds the cluster, the page it maps to and the keywords in it.